Share of Power
In a democratic country, the fate of political parties is highly dependent on the support of the people who are free to make political choices.
General elections or pemilu are only meaningful for the people at large if they help solve their problems, for example the problems of health, education, workers' rights, housing or sexual violence. Elections are also all-important if their results impact a constitutional overhaul or global policies, such as climate change or foreign relations.
In any country all these problems are too heavy for one political party to handle. Let alone for one politician. How redundant it is to discuss the electability of individual presidential candidates if they are not the strongest politicians from one of the strongest parties.